It is desirable to measure the pressure inside a pump chamber. In some fields, pumps have decreased in size such that the placement of stress gauges on the housing of the pump has become difficult. For example, for pumps used in liquid chromatography it is desirable to operate at pressures greater than 3,000 pounds per square inch (psi). This pressure represents the normal upper limit of conventional chromatographic apparatus. Pressures in the ultra pressure region of greater than 4,000 up to 12,000 psi are desired. To attain these high pressures pump chambers are machined with greater precision. There is less area in the pump chamber to receive connections to pressure sensors.